1. Field of the Invention
The present invention relates to an insert conductor used as a component of a brush holder incorporated in, for example, a vehicular charging generator.
2. Description of Related Art
FIG. 8 is a sectional side elevation showing a conventional vehicular charging generator which is equipped with: a case 3 constituted by an aluminum front bracket 1 and a rear bracket 2; a shaft 6 which is provided in the case 3 and which has a pulley 4 fixed on one end thereof; a rotor 7 fixed on the shaft 6; a fan 5 fixed on a side surface of the rotor 7; a stator 8 fixed on an internal surface of the case 3; a slip ring 9 which is fixed on the other end of the shaft 6 and which supplies current to the rotor 7; a pair of brushes 10 which slide on the slip ring 9; a brush holder 11 which houses the brushes 10; and a rectifier 12 which is electrically connected to the stator 8 to rectify the alternating current generated in the stator 8 into direct current.
The vehicular charging generator is equipped with: a heat sink 17 fitted in the brush holder 11; a regulator 18 which is bonded to the heat sink 17 and which regulates the magnitude of the AC voltage generated in the stator 8; and a ventilation guide 19 which is fixed on an outer peripheral section of the brush holder 11 and which guides an airflow generated by the rotation of the fan 5 to the regulator 18 and a stator coil 16.
The rotor 7 is provided with a rotor coil 13 through which a current flows so as to generate a magnetic flux, and an iron, hook-shaped field core 14 which covers the rotor coil 13 and forms a magnetic pole with the magnetic flux.
The stator 8 is equipped with a stator core 15 and the stator coil 16, the conductor of which is wound around the stator core 15 and generates alternating current as the magnetic flux of the rotor 7 changes when the rotor 7 rotates.
In the vehicular charging generator having the configuration described above, current is supplied from a battery, not shown, to the rotor coil 13 via the brushes 10 and the slip ring 9 to generate a magnetic flux, thus forming the magnetic pole in the field core 14. The pulley 4 is driven by an engine and the rotor 7 is rotated by the shaft 6; therefore, the rotating magnetic field is applied to the stator coil 16, and an electromotive force is generated in the stator coil 16.
The first short circuit preventing cover 29a and the second short circuit preventing cover 29b have a U-shaped cross-section, and the third short circuit preventing cover 29c is arc shaped.
The method of manufacturing the brush holder 11 having the aforesaid configuration will now be explained.
First, an iron sheet is subjected to stamping to form a conductor 31 shown in FIG. 11. The conductor 31 has an outer frame 32 and a wiring section 34 connected to the outer frame 32 via connections 33. The wiring section 34 is composed of a plurality of wires 37 connected via the connections 33.
Next, the conductor 31 is subjected to insert resin molding to form a molded unit 36 in which the brush holder main body 22 has been formed on the conductor 31 as shown in FIG. 12.
In the following step, the respective connections 33 are cut by stamping to make the brush holder 11 shown in FIG. 13. FIG. 13 is a rear view of the brush holder 11 shown in FIG. 9.
In designing the brush holder, there are some cases in which, for example, the connector terminals for wiring cannot be positioned in the same plane in the conductor, and the brush holder must be manufactured by having the connector terminals stacked in the middle of the manufacturing process.
FIG. 14 is a front view illustrating a conductor 41 used in the foregoing cases; and FIG. 15 is a front view illustrating a first connector terminal 42 and a second connector terminal 43 combined on the conductor 41.
The conductor 41 has an outer frame 44 and a wiring section 46 connected to the outer frame 44 via connections 45. The wiring section 46 is composed of a plurality of wires 52 interconnected via the connections 45.
The first connector terminal 42 and the second connector terminal 43, which are discrete wires, have engaging holes 47 and 48, respectively, in the middle portions thereof.
In this case, to form a molded unit 49 as shown in FIG. 16, it is necessary to prepare a metal mold provided with pins which penetrate the engaging holes 47 and 48 to position the first and second connector terminals 42 and 43 in relation to the conductor 41. Hence, at the rear of the molded unit 49 shown in FIG. 16, a brush holder main body 50 has pin apertures 51 as illustrated in FIG. 17.
The conventional brush holder 11 shown in FIG. 9 has the following problems: the connections 33 are cut after molding the brush holder main body 22, and portions of the wiring i.e. the exposed portions 28a, 28b, and 28c, are therefore partly exposed to the outside, so that moisture, for example, adheres to those exposed portions 28a, 28b, and 28c, leading to the possibility that the wire will become disconnected due to galvanic corrosion and dissolution.
Further, in order to prevent a short circuit between the exposed portions 28a, 28b, and 28c and the rear bracket 2, the ventilation guide 19 must be provided with the first, second, and third short circuit preventing covers 29a, 29b, and 29c. This inevitably makes the entire configuration of the ventilation guide 19 complicated, and the configuration of the mold for making the ventilation guide 19 accordingly becomes complicated, resulting in higher manufacturing costs for the ventilation guide 19.
Furthermore, in another conventional brush holder, the first and second connector terminals 42 and 43, shown in FIG. 14, are positioned with respect to the conductor 41 by the pins formed on the mold, so that the pin apertures 51 remain in the brush holder main body 50 as shown in FIG. 17. This presents a problem in that the internal surfaces of the engaging holes 47 and 48 of the first and second connector terminals 42 and 43, respectively, are inevitably exposed to the outside through the pin apertures 51, so that moisture enters through the pin apertures 51, leading to the possibility that the wire 52 will become disconnected due to galvanic corrosion and dissolution as in the case of the brush holder 11 mentioned previously.
There has been yet another problem in that the pins engaging with the engaging holes 47 and 48 must be formed on the mold, adding to the manufacturing cost of the mold.